gistfile1.hs

module Main where
  
import Criterion
import Control.Concurrent.CHP.Monad
import Data.IORef

import qualified Data.Map as M
import Progression.Main
import Random

import System.IO.Unsafe

runAll = defaultMain . bgroup "" . map (\c@(a,b) -> bench a ( b))
main = runAll [("SimpleCalc", Main.run)
              ,("SimpleCalc Memoised1", Main.runm)
              ]

run :: IO ()
run =  genList >>= (putStrLn . show . map calc)


runm :: IO ()
runm = do xs <- genList
          store <- newIORef M.empty
          (putStrLn.show) $ map (calcM store) xs

-- | Yes, I'm very sorry about the unsafePerformIO here. And no, my name is not
--   Simon unfortunately. :)
calcM :: IORef (M.Map Int Integer) -> Int -> Integer
calcM storevar a = unsafePerformIO $
                   do store <- readIORef storevar
                      maybe (do let result = calc a
                                writeIORef storevar (M.insert a result store)
                                return result
                            )
                            return
                            (M.lookup a store)

calc :: Int -> Integer
calc = fib


genList :: IO [Int]
genList =  do g <- newStdGen
              return $ take 10000 $ randomRs (1,25) g
              

fib :: Int -> Integer
fib n
    | n == 0  = 0
    | n == 1  = 1
    | n  > 1  = fib (n-1) + fib (n-2)